That' really depends on your needs. Magento has the ability to run a wordpress instance on it. They allow that since they know the power of wordpress. You can also run the ecommerce part on a subdomain like shop.yourdomain.com and not effect the wordpress part of your site. It's never a good a idea to tear down a website that is working and getting your rankings, and put it on a new CMS since "someone" recently told you.
I would recommend attempting to run Magento on a subdomain, and interlinking your wordpress with Magento. I'm not a big fan of Magento since it's utilizing 2 engines to get the job done of one engine.
This might sound like I'm trolling but I in November, I recently helped a big brand move to Magento, and it was a fucking nightmare. I was literally sitting there with 2 FedEx coders in a hot ass warehouse in Miami attempting to get the shipping down for weeks on end. I don't plan on doing that again, I use simple shit that makes my life easy and fuck, and database integration easy as well. I use Zen cart, yeah, It looks like SHIT, but it works, and is fast as fuck.
When do I need quick access to database integration? well when FedEx tracking system has to be manually implemented, on Magento, it's a fucking nightmare to check off the 100 something fucking tables they have when mimicking a trigger. It had a lot of customization, which took me well over 120 hours in just programming. At $125 an hour, that shit was expense for the client. Magento's too bulky, and lacks grace and zen when it comes to coding. The shit is slow.
I was talking to the owner of PrestaShop recently and going back and forth about their shopping cart, and doing comparisons. They are a french company, with a new office in Miami, but they seem to have a solid foundation, and the owner is a complete dick when it comes to standards, which is what I love, so I plan on using them in for future shopping carts.
Just my 2 cents.
